材料期刊网

Herein,we report a simple and effective preparation of ultrafine CNFs (u-CNFs) with high surface area via electrospinning of two immiscible polymers [polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA)] followed by calcination at high temperature in an inert atmosphere.Various electrospinning conditions were optimized in detail.Four different kinds of PAN/PMMA ratios (10/0,7:3,5:5 and 3:7)were chosen and found that the PAN/PMMA ratio of 3:7 (PAN/PMMA-3:7) is the optimum one.BET analysis showed the specific surface area of the u-CNFs-3:7 was 467.57 m2/g with an excellent pore volume (1.15 cm3 g-1) and an average pore size (9.48 nm):it is about 25 times higher than the conventional CNFs (c-CNFs).TEM and FE-SEM images confirmed the ultrafine structure of the CNFs with a thinner fiber diameter of～50 nm.The graphitic nature and atomic arrangement of the u-CNFs were investigated by Raman and XPS analyses.For the supercapacitor application,unlike the common electrode preparation methods,the u-CNFs-3:7 was used without any activation,chemical or mechanical modifications.The u-CNFs3:7 showed a better specific capacitance of 86 F/g in 1 mol/L H2SO4 when compared to pure CNFs.The excellent physicochemical properties make the u-CNFs-3:7 an alternative choice to the existing CNFs for the supercapacitors.